—Is Mary sure _______ the exam?—I think so. She is good at math. I’m sure ______ she can pass it.
——What if you have two days_______?——I'd like to go_______ a trip_______ Suzhou.
You______buy Tom a present if he invites you to his birthday party.
This umbrella is____that one,but____than that one.
The 6-year-old child is old enough_______ himself.
Shanghai is bigger than______in Jiangsu and bigger than______in China.